Sierpinski square curve: Difference between revisions
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{{out}}
Output is similar to C++.
=={{header|Ada}}==
Creates an SVG file.
<syntaxhighlight lang="ada">
with Ada.Numerics; use Ada.Numerics;
with Ada.Numerics.Elementary_Functions; use Ada.Numerics.Elementary_Functions;
with Ada.Text_IO; use Ada.Text_IO;
with Ada.Strings.Unbounded; use Ada.Strings.Unbounded;
procedure Sierpinski_Square_Curve is
Axiom : constant String := "F+XF+F+XF";
Rules : constant String := "XF-F+F-XF+F+XF-F+F-X";
ORDER : constant Positive := 5;
LENGTH : constant Positive := 4;
X : Integer := (600 - LENGTH) / 2;
Y : Integer := LENGTH;
Angle : Integer := 0;
SVG_File : File_Type;
Production : Unbounded_String := To_Unbounded_String (Axiom);
function Rewrite (Str : String) return Unbounded_String is
Prod : Unbounded_String;
begin
for C of Str loop
if C = 'X' then
Prod := Prod & Rules;
else
Prod := Prod & C;
end if;
end loop;
return Prod;
end Rewrite;
begin
Create (SVG_File, Out_File, "sierpinski.svg");
Put_Line (SVG_File, "<svg xmlns='http://www.w3.org/2000/svg' width='600' height='600'>");
Put_Line (SVG_File, "<rect width='100%' height='100%' fill='white'/>");
Put (SVG_File, "<path stroke-width='1' stroke='black' fill='none' d='M" &
X'Image & "," & Y'Image & " ");
for I in 1 .. ORDER loop
Production := Rewrite (To_String (Production));
end loop;
for C of To_String (Production) loop
case C is
when 'F' =>
X := X + LENGTH * Integer (Cos (Float (Angle), 360.0));
Y := Y + LENGTH * Integer (Sin (Float (Angle), 360.0));
Put (SVG_File, " L" & X'Image & "," & Y'Image);
when '+' => Angle := (Angle + 90) mod 360;
when '-' => Angle := (Angle - 90) mod 360;
when others => null;
end case;
end loop;
Put_Line (SVG_File, "'/>\n</svg>");
Close (SVG_File);
end Sierpinski_Square_Curve;
</syntaxhighlight>
=={{header|ALGOL 68}}==
Generates an SVG file. The SVG generating code is translated from the FreeBASIC sample (which is a translation of the 11l sample which is translated from the C++). Uses the Algol 68 library for L-System related Tasks on Rosetta Code.
{{libheader|ALGOL 68-l-system}}
Note: The source of the Algol 68 L-System library is available on a separate page on Rosetta Code - see the above link and follow the link to the Talk (Discussion) page.
<syntaxhighlight lang="algol68">
BEGIN # Sierpinski Square Curve in SVG - SVG generation translated from the #
# FreeBASIC sample (which is a translation of C++) #
# uses the RC Algol 68 L-System library for the L-System evaluation & #
# interpretation #
PR read "lsystem.incl.a68" PR # include L-System utilities #
PROC sierpinski square curve = ( STRING fname, INT size, length, order )VOID:
IF FILE svg file;
BOOL open error := IF open( svg file, fname, stand out channel ) = 0
THEN
# opened OK - file already exists and #
# will be overwritten #
FALSE
ELSE
# failed to open the file #
# - try creating a new file #
establish( svg file, fname, stand out channel ) /= 0
FI;
open error
THEN # failed to open the file #
print( ( "Unable to open ", fname, newline ) );
stop
ELSE # file opened OK #
REAL x := ( size - length ) / 2;
REAL y := length;
INT angle := 0;
put( svg file, ( "<svg xmlns='http://www.w3.org/2000/svg' width='"
, whole( size, 0 ), "' height='", whole( size, 0 ), "'>"
, newline, "<rect width='100%' height='100%' fill='white'/>"
, newline, "<path stroke-width='1' stroke='black' fill='none' d='"
, newline, "M", whole( x, 0 ), ",", whole( y, 0 ), newline
)
);
LSYSTEM ssc = ( "F+XF+F+XF"
, ( "X" -> "XF-F+F-XF+F+XF-F+F-X"
)
);
STRING curve = ssc EVAL order;
curve INTERPRET ( ( CHAR c )VOID:
IF c = "F" THEN
x +:= length * cos( angle * pi / 180 );
y +:= length * sin( angle * pi / 180 );
put( svg file, ( " L", whole( x, 0 ), ",", whole( y, 0 ), newline ) )
ELIF c = "+" THEN
angle +:= 90 MODAB 360
ELIF c = "-" THEN
angle +:= 270 MODAB 360
FI
);
put( svg file, ( "'/>", newline, "</svg>", newline ) );
close( svg file )
FI # sierpinski square # ;
sierpinski square curve( "sierpinski_square.svg", 635, 5, 5 )
END
</syntaxhighlight>
{{out}}
Similar to FreeBasic, 11l, C++, etc.
=={{header|ALGOL W}}==
Line 467 ⟶ 590:
{{out}}
<pre>Output is similar to C++.</pre>
=={{header|Fōrmulæ}}==
{{FormulaeEntry|page=https://formulae.org/?script=examples/L-system}}
'''Solution'''
It can be done using an [[wp:L-system|L-system]]. There are generic functions written in Fōrmulæ to compute an L-system in the page [[L-system#Fōrmulæ | L-system]].
The program that creates a Sierpiński's square curve is:
[[File:Fōrmulæ - L-system - Sierpiński's square curve 01.png]]
[[File:Fōrmulæ - L-system - Sierpiński's square curve 02.png]]
=={{header|Go}}==
Line 971 ⟶ 1,108:
=={{header|Quackery}}==
Method is described at [[L-system#Quackery]].
<syntaxhighlight lang="quackery"> [ $ "turtleduck.qky" loadfile ] now!
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